Vibratory mechanism



" May 17, 1960 D. s. CUSI 2,936,895

VIBRATORY MECHANISM FiledApril 18, 1955 s Sheets-Sheet 1 INVEN'i'OR DANTE s. CUSI ATTORNEY May 17, 1960 D. s. CUSI VIBRATORY MECHANISM 3 Sheets-Sheet 3 Filed April 18, 1955 64 IO c 400 FIG. 3.

INVENTOR DANTE 8. Gus! BY f ATTORNEY United States This invention relates to vibratory mechanism generally and particularly to vibratory apparatus adapted to'screen solid particles of a suspension from the liquid in which they are suspended.

In the manufacture of paper serious difficulties are encountered in separating various pulp types. In the manufacture of paper from Bagasse, in particular, it is necessary that the various fiber types be completely separated. Due to the large amount of material which is re ected, particularly in the early stages of the separating processes, as, for example, in the separation of pith from the fibers, it has been found that prior art screening mechamsms would not function properly. This is due tothe fact that the material to be rejected is of such a mass that it forms a mat on the screen, making it impossible for the smaller acceptable particles to be passed. The present invention provides for screening material of this type by the novel procedure of maintaining a predetermined amount of liquid above the screen so as to prevent matting and like difficulties. The receptacle or enclosure which is adapted to receive the acceptable partrcles is provided with a plurality of sections having means to adjust the height of the suspension therein. In eflfect, a series of dams is provided, these dams maintaining a predetermined amount of liquid over the screen. The screen is vibrated to cause the particles and suspension to move over the screen and a portion of the receptacle is provided with a flexible deformable bottom so that'as the 2 of liquid suspension is maintained over the screen during the screening operation. 4

Still another object of this invention is to provide a vibratory apparatus in which relative movement between the screen and the liquid suspension is assured.

A further object is to provide a novel vibration-imparting mechanism which aifords the desired controlled vibration to the screen without adding unduly to the cost or complexity of the apparatus.

In the drawings:

Fig. 1 is a perspective view, partly broken away, of the apparatus; 7 v

Fig. 2 is a longitudinal vertical section through the machine along the lines 2-2 of Fig. 5

Fig. 3 is an elevation view partly in section, along the lines 3-3 of Fig. 2;

Fig. 4 is a vertical section along the 3; and

5 is a Fig. 3.

The apparatus as a whole consists of a rectangular enclosure having side Walls 2 and 4, end walls 6 and 8 and a bottom indicated generally at 10 in Fig. 1 of a construction to be described. Extending longitudinally of the apparatus, parallel to the partition frame members 12 and 14'which define three channels extending longitudinally of themachine. The screening channel 20 defined laterally by the partitions 12 lines 44 of Fig.

horizontal section along the lines 5 -5 of and 14 is of substantial width and contains ascreen plate 22 submerged in the liquid suspension as it flows from the ,iinlet 24 at the right hand end of the machine as viewed in Figs. 2and 4 toward the left hand end. The inlet 24 screen and receptacle move upwardly the inertia'of the liquid suspension deforms the bottom. When the screen and enclosure move downwardly, the bottom is restored to its original position. In this way relative movement is produced between the screen and liquid suspension which assists in the screening operation and serves to'prevent matting. The acceptable fiber passes through the screen and through a discharge chute while the unacceptable fiber remains on the screen and is removed at the end of the screen. I

By providing means for adjusting the" liquid'hea'd in various sections of the screen so that .a'predetermined amount of liquid is passed throughthe screenin each' sec' tron, 1t can be seen that the consistency of the suspension above the screen may be set as desired so that matting does not occur. The efiiciency of the screening operation is further enhanced by the flexible bottom on thereceptacle which assures relative movement between'the screen and the suspension. Thus, the present invention provides an apparatus for screening fiber types where a large amount of rejected material is present and which prior art methods and apparatus were incapable of screening efiectively.

An object of the present invention is to provide a vibratory apparatus for screening material in a'liquid suspension Where a large amountof rejected material is present.

Another object of the present invention is to provide a vibratory apparatus in which a'predetermined amount communicates with the channel 20 through the opening 26 above the screen 22 as shown in Fig. 2. Channel 30 (Figs. 1 and 3) is narrower than channel 2i and is defined between partition 12 and side wall 2. A similar channel 32 is formed between the opposite side wall 4 and the adjacent partition 14. 1

Mounted at spaced intervals lengthwise of the channel .20is a series of ribs 40 extending transversely of the channel and suitably'secured to side partitions 12 and 14. These ribs are preferably fixed in height and are convexly curved at their upper surfaces as indicated, at 42 for the rib 40a in Fig. 3 to support the screen 22 in the arcuate shape indicated. The screen may be and preferably is constructed in the manner described in my co pending application Ser. No. 473,617 filed December 7, 1954, now Patent No. 2,827,169. The screen is suitably secured in its position on the upper arcuate surfaces of the ribs 40 with its marginal edges in close abutment against the inner surfaces of the side partitions 12 and 14. The side channels 30 and 32 have weirs 50 and 52 in transverse alignment with each other and with the ribs 40in the central channel and conveniently the corresponding weirs in the two outer channels and the ribs in the central channel may be constructed of a single plate extending through the side partitions 14 and 12 to the side walls 4 and 2 respectively. 7 a V The weirs 50 and 52 in the side channels are adjustable .in height which may readily be accomplishcdrin'any to the desired height.

The bottom 10 of the enclosure consists of the plate 10a, Fig. 3, forming the bottom of the channel 30 and the plate 10b forming the bottom of the channel 32 and the rubber diaphragm 10c forming the bottom of the central channel 20. The diaphragm is suitably sup.-

side walls 2 and 4, are the 3 ported as by bolts 64 firmly attaching the diaphragm to the bottom edges of the ribs 40.

The pairs of adjacent ribs 40 in the central channel 20 define transversely extending rectangular passages 70 bounded at the top by the screen 22 and at the bottom by the rubber diaphragm. c and opening laterally through the apertures 72 for communication with the side channel 30. At their opposite ends the transverse passages 70 communicate through corresponding passages 74 (Fig. 3) with the side channel 32.

At the left hand end of the machine as viewed in Figs. 2, 4 and 5, is an outlet 80 communicating with the outlet for channels 30 and 32.

For a purpose which will appear the screen 22 is ele vated slightly at its outlet end 22a and is suitably supported in elevated position.

Although the machine is shown with its longitudinal axis extending horizontally, for convenience in illustration, the apparatus above described may be arranged with its axis sloping downwardly from the inlet end of the apparatus toward the outlet to induce flow of the suspension toward the outlet end of the machine.

The apparatus above described is mounted on compression springs 100 at the four corners of the apparatus symmetrically about the vertical axis through the center of gravity of the machine. These spring mountings permit vibration of the apparatus by the operation of the vibration imparting mechanism now to be described.

The side partitions 12 and 14 extend upwardly and inwardly as indicated at 1211 and 141: to form a support with two other upwardly converging side plates 110 and 112 to support a platform 114 on which is mounted bearings 116, 118, Fig. 2, which rotatably support a shaft 120 connected through suitable universal or flexible joints 122 and 124 with a motor 125. The shaft 120 carries secured to it a pair of flywheels 130 and 132, each of which, as indicated in Fig. 2, carries a pair of weights 140 and 142 which may be adjusted from a position diametrically opposite each other when the flywheel will be in balance during rotation of the shaft to a position on a common side of a diameter when the Weights will impart an unbalance to the rotating system.

In operation both flywheels are out of balance. The

axis of the shaft 120 is in vertical alignment with the center of gravity of the apparatus as a whole and by this mechanism, which'is simple in construction, I have found that a vertical vibration of high frequency can be imparted to the apparatus as a whole, particularly the screen 22, with-very little lateral vibration. This is due to the fact that the center of gravity of the apparatus lies in the screen so that there is little tendency for the screen and portions of the apparatus surrounding the screen to vibrate laterally. Thus, a vertical vibration is imparted to the screen.

In operation the machine constructed as above described and mounted so that it inclines downwardly toward its outlet end is charged with the suspension to be screened, composed of fibrous material suspended in water. The machine is charged continuously to a depth which may approximate the dash line 154 Fig. 3, and the vibration imparting mechanism is started in operation. The machine as a whole, including the screen 22, oscillates vertically but the liquid contained in the central channel 20 has a different motion resulting from the elasticity of its support on the rubber diaphragm 10c. Considering a single vertical reciprocation of the apparatus, when the screen moves upwardly the inertia of the liquid mass on the diaphragm cause the diaphragm to yield downwardly so that the screen moves upwardly relative to the liquid mass. When the screen then moves downwardly the rubber diaphragm is restored so that there is less downward movement of the liquid than the screen, resulting in a downward movement of the screen relative to the liquid. By this relative motion, rapidly repeated in successive oscillations, the fibrous solids are kept in suspension in the liquid and matting 9n the screenis inhibited and the holes become freed of clogging particles.

The flow of material and the function of the weirs can be illustrated by considering, for example, a portion A of the suspension which at the moment illustrated in Fig. 2, is above a section 22x of the screen. Part y of this portion A will pass down the screen, as indicated by the arrow, as the result of the lead of the apparatus downwardly to the left, and another part x will pass through the section 22x of the screen into the transverse passage 70x (Fig.1) beneath it. Of the part x some will now pass through the aperture 72x into the channel 30 and part will pass through the corresponding aperture 74 on the opposite side of the apparatus into the channel 32. The part passing through aperture 72x will tend to flow toward the outlet of the machine but will be met by the weir Stlx tending to obstruct its flow. That portion which passes over the weir 50x will continue down the channel 30 toward the outlet as it is permitted by the successive weirs 50 which it encounters. The rate at which the components of the suspension, passed by the screen, flow downwardly through the screen, in this instance the portion x, depends in part upon the diiferenc'e in the hydrostatic pressure of: the liquid above the screen tending to force the suspension downwardly and the hydrostatic pressure beneath the screen tending to resist such downward flow. The purpose of the side channels with their adjustable weirs is to vary these relative hydrostatic heads, for each given section of the screen through the machine. Thus, in the example illustrated, the height of the weir 50x, which may be adjustable as above described, determines the hydrostatic head in the liquid immediately behind it. This head is illustrated by the dash line 2% in Fig. 3. It will be noted that the level 200 is below the level indicated at in channel 20. The difference 291 in level represents the order of magnitude of the hydrostatic head tending to induce flow downwardly through the screen, and this can be varied as above referred to.

In practice the components of the suspension of .a size to be passed through the screen will more readily pass through it in the initial sections of the screen engaged by the suspension on entering the apparatus than those sections of the screen disposed nearer the outlet 7 of the apparatus. Thisis for the reason that the concentration of the suspension in those fibrous materials that are rejected by the screen increases toward the outlet end. Consequently, a greater difference in hydrostatic head would be needed near the outlet end of the machine and the weirs in the side channels will be adjusted accordingly.

I claim:

,1. Apparatus for screening a liquid-solid suspension comprising a container for the suspension, side walls extending longitudinally of the container forming a channel for the reception'of the liquid-solid suspension to be screened, a plurality of partitions extending transversely of the channel dividing it into transverse sections, a screen resting on said partitions and extending between the side walls adapted to be submerged in the liquid contained in the channel, and means to adjust the hydrostatic head of the liquid suspension in each section of the'channel independently of that of the other sections.

2. Apparatus for screening a liquid-solid suspension comprising a container ,for the suspension, side walls extending longitudinally of the container forming a channel for the reception of the'liquid-solid suspension to be screened, a plurality of partitions extending transversely of the channel dividing it into transverse sections, a screen resting on said partitions and extending between the side walls adapted to be submerged in the liquid contained in the channel, a side channel extending longitudinally of the container having aplurality of transverse weirs dividing the side channel into transverse sections in alignment withcorresponding sections of the central channel, passages torming communications .between the corre- 3. Apparatus for screening a liquid-solid suspension comprising a container for the suspension, side walls extending longitudinally of the container forming a channel for the reception of the liquid-solid suspension to be screened, a plurality of partitions extending transversely of the channel dividing it into transverse sections, a screen 1 resting on said partitions and extending between the side walls adapted to be submerged in the liquid contained in the channel, means to adjust the hydrostatic head of the liquid suspension in each section of the channel independently of that of other sections, means for oscillating the container in a vertical direction, and an elastic membrane forming the bottom of the channel on which the liquid rests, secured to the container to oscillate vertically therewith and being freely suspended to yield under the inertia of the liquid mass when the container is oscillated vertically. I

4. Apparatus for screening a liquid-solid suspension comprising a container for the suspension, side walls extending longitudinally of the container forming a channel for the reception of the liquid-solid suspension to be screened, a plurality of partitions extending transversely of the channel dividing it into transverse sections, a screen resting on said partitions and extending between the side walls adapted to be submerged in the liquid contained in the channel, aside channel extending longitudinally of the container having a plurality oftransverse weirs dividing the side channel into transverse sections in alignment with corresponding sections of the central channel, passages forming communications between the corresponding sections of the central and side channels, the weirs being individually adjustable to vary the liquid level in each section of the side channel relative to the liquid level in the corresponding section of the central channel for selective adjustment of the hydrostatic head in each section of the central channel independently of that of the other :sections of the central channel, means yieldable in a vertical direction for resiliently supporting the container, means for oscillatingthe container in a vertical direction,

and an elastic membrane forming the bottom of the central channel on which'the liquid rests, secured to the container to oscillate vertically therewith, the said membrane being deformable, under the weight of the liquid,

throughout substantially its entire surface area, and being freely suspended to yield under the inertia of the liquid mass when the container is oscillated vertically.

References Cited in the file of this patent UNITED STATES PATENTS 

